More Black Friday Headlines

"We have not been able to confirm any shots being fired nor anyone who witnessed anyone shooting," Sgt. Eddie Rodriguez said about 3 p.m.

Security at the mall reported someone decided to pull the fire alarm after something fell and caused a loud noise. Shoppers scattered and police officers flooded the busy mall about 1:50 p.m., but after about 30 minutes they had found no sign of any gunshots, a suspect or casualties.

Rodriguez said detectives were still investigating what set off the security alert.

Three major stores -- Macy's, JC Penney and Sears -- anchor the mall, which reopened about 2:35 p.m. Other popular stores include H&M, Victoria's Secret, G by Guess, Pandora and Tous.

People in crowded places in the United States and Europe have been jumpy due to a series of mass shootings and terror attacks.